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Variable Flow Pump system with VFD

Variable Flow Pump system with VFD

Variable Flow Pump system with VFD

(OP)
Hi all:

I am involved as electrical engineer in the designing of pump system for loading refrigerated products (PROPANE, BUTANE) to ships. This system will have a wide range of flow quantity since will be many different ships with many different capacities and flow rate limits. I am proposing a system of three pumps, 900HP each (2 operating and 1 spare). Just 1 pump will be drived by a VFD.

What should I consider to make a good design?
Should I specify the motor and the VFD in 460 V or in 4.16KV?

Thanks in advance.  

 

RE: Variable Flow Pump system with VFD

Hard to say with that info.

1.4MW.

460 will probably cost less and doesn't require specially trained installers.  It is rather borderline.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Variable Flow Pump system with VFD

(OP)
Thanks itsmoked:
Just to clarify, I am thinking in just 1 VFD..(1 pump will be driven by just 1 VFD)900 HP, 675KW.

The second one will be operated directly to line, and the third one will be just in spare.

RE: Variable Flow Pump system with VFD

A big LV VFD will be much cheaper than a small MV one. If this was not a VFD application I would say go with the MV solution. If you have other MV motors and the staff to look after them I would think the economics will favour the two fixed speed pumps being MV and the variable speed pump being LV.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Variable Flow Pump system with VFD

Except Scotty when the VFD motor takes a dump and the spare is MV.   I think they all need to be the same.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Variable Flow Pump system with VFD

(OP)
This is a new project, for a new plant. And actually, it is difficult propose a 460 V motor for that power, because, the motor shal be capable to start with direct voltage.I have read about some "new" arrangement to control flow with several breakers, a small control logic and just 1 VFD to control up to 3 of 4 motors.
I am not with the mechanical considerations and the isolating transformer that should be used.

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